<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		
		<script type="text/javascript">
			if (true) {
			    let i = 0;
			}
			console.log(i); // 输出？
			//输出i is not defined,因为i变量只在花括号内有效,括号外的打印输出接收不到。
		</script>
	</body>
</html>
